This is a link to a google workbook that contains a list of all of the engravings for Naoe and Yasuke. The engravings are listed in grid format, so you can copy them down, sort them, etc. They include all of the hints except for ones that I unlocked before making the list. In those instances, you should still have the hint in your game. Some engravings are listed twice if I found them looting in a place that didn’t match up with the given hint.
Also, some engravings are listed to be at merchants that I assume are the gear merchants, but I haven’t been able to confirm they’re there. The Vendor’s wares don’t appear to be dependent on seasons or anything.
Google workbook is here. If you cannot access it, please email me (contact page) b/c that means a setting needs to be changed.